tuple_1 = (1, 2, 3)  # tuple(元组类型)
tuple_2 = 4, 5, 6  # tuple(元组类型)

# 元组的不可变特性
list_1 = [1, 2, 3]
list_1[0] = 4
# 'tuple' object does not support item assignment (不可变）
tuple_1[0] = 4
tuple_3 = (3, 4, [5, 6, 7])  # 元组中嵌套列表 列表可进行改变
tuple_3[2][2] = 8  # (3, 4, [5, 6, 8])

a = ('str', 1, 4, 5, 'str')
a.count('str')  # 次数2
a.index('str')  # 返回 0 重复出现的str 第一个返回索引
